1. Field of the Invention
This invention relates to a magnetic head device for use in a video-tape recorder, a magnetic disc apparatus, or the like and a method of producing the magnetic head device, and more particularly to a magnetic head device provided with a coil formed by a thin film formation process and a method of producing such a magnetic head device.
2. Prior Art
A variety of magnetic heads have been employed for magnetic recording/reproducing apparatuses such as video-tape recorders (VTR), magnetic disc apparatuses or the like. Typical conventional magnetic heads include, for example, so-called metal-in-gap type magnetic heads composed of a magnetic core made of ferrite and a metal magnetic film layer formed on a magnetic-gap forming surface of the magnetic core, laminate-type magnetic heads composed of a pair of base members made of a non-magnetic material and a metal magnetic film layer interposed between the pair of base members, or the like. In such a field, in order to meet the requirements such as a high image quality, a digitalized information data, etc., there is an increasing demand for magnetic heads having a good electro-magnetic transformation characteristic in a high-frequency region.
However, the metal-in-gap type magnetic heads are not usable in the high-frequency region due to its large impedance.
On the other hand, in the laminate-type magnetic heads, in case that a track width of recording medium should be decreased to meet a requirement of a high-densification thereof, it is necessary to reduce a thickness of the metal film layer defining a magnetic path. This results in deterioration of a reproduction efficiency. Further, since the magnetic path is formed by the metal magnetic film layer solely, there occurs a problem in controlling a magnetic anisotropy thereof, which makes it difficult to obtain a high reproduction efficiency. That is, an ideal condition for a magnetic anisotropy of magnetic head is generally that an axis of easy magnetization of the metal magnetic film layer is always oriented perpendicular to the direction of magnetic flux. However, it is actually difficult to maintain the perpendicular orientation of the axis of easy magnetization so that only a magnetically isotropic (non-orientation) metal film or uniaxial magnetic anisotropy metal film have been used for the magnetic head.
In order to render the magnetic head usable in a high-frequency region, there has been proposed a magnetic head device provided with a magnetic head chip in which a magnetic path defined by a metal magnetic film is reduced as compared with those of normally used magnetic heads and a thin film coil is formed on a magnetic gap-forming surface by using a thin film formation technique, for example, as disclosed in Japanese patent laid-open publications Nos. 231,713/88 and 248,305/91.
Conventionally used magnetic heads are shown in FIGS. 1 through 5. The magnetic head shown in FIG. 1 is composed of a magnetic head chip 101 provided thereon with a thin film coil, a head base 102 on one surface of which the magnetic head chip 101 is mounted, and a terminal plate 111 generally mounted on the opposite surface of the head base 102. Formed on the terminal plate 111 are printed wiring boards 112 and 113 having terminals 112a and 113a, respectively, which are electrically connected with terminals 117 of the thin film coil through sheathed wires 114 by using a soldering or a conductive adhesive 115. The connecting portions between respective terminals of the printed wiring boards 112 and 113 and the magnetic head chip are covered with a molded resin 116.
Further, there has been a recent demand for a compactness of a rotating drum to which a magnetic head is mounted. In association with such a demand, primarily those for accomplishing a thin thickness of the rotating drum, there has been proposed a magnetic head in which the head chip 101 and the terminal plate 111 are mounted on the same surface of the head base as shown in FIGS. 2 to 5. In the preparation of such a magnetic head as shown in FIG. 2, after mounting the head chip 101 on a primary surface of the head base 102, the terminal plate 111 is fixedly bonded on the same primary surface of the head base 102, as shown in FIG. 3.
Successively, as shown in FIG. 4, one end of each of the sheathed wires 114 is in contact with each terminal of the head chip 101 and electrically connected therewith by using a soldering or a conductive adhesive 115. The other end of each of the sheathed wires 114 is then in contact with each of the terminals 112a and 113a of the printed wiring boards 112 and 113 and electrically connected therewith by using a soldering or a conductive adhesive 115. Thereafter, the connecting portions between the head chip 101 and printed wiring boards 112 and 113 is covered with the molded resin 116.
The thus constructed magnetic head is mounted on a rotating drum (not shown) in such a manner that the head base 102 with the head chip 101 is fitted, on a side of its surface where the terminal plate 111 is not mounted, to the rotating drum. The rotating drum is provided with a rotary transformer which is electrically connected with the other ends of terminals 112 and 113 through sheathed wires by using a soldering or a conductive adhesive.
However, in the preparation of the conventional magnetic heads, it is difficult to maintain the sheathed wires 114 between the terminals 112 and 113 of the terminal plate 111 and the terminals 115 and 116 of the thin film coil provided on the head chip 101 until they are connected with each other. This results in not only complicated operational procedures but also an increase in risk of generating the damage to the sheathed wires by contact with hands when the magnetic head is inverted whereby a yield or a reliability of the product are considerably deteriorated. Furthermore, necessity of the wiring steps for the sheathed wires 114 or the like leads to increase in number of assembling processes so that it becomes extremely difficult to achieve reduction of the production cost.